Color Bar Missing in Ggplot Legend, Windows Remote Desktop

Color bar missing in ggplot legend, Windows Remote Desktop

I found the problem, and a working solution, here. It's an issue with color rendering when accessing a server via Remote Desktop, and can be fixed in host settings.

Continuous color bar with separators instead of ticks

There definitely is an option with the extendable guide system introduced in ggplot v3.3.0. See example below:

library(ggplot2)

guide_longticks <- function(...) {
  guide <- guide_colorbar(...)
  class(guide) <- c("guide", "guide_longticks", "colorbar")
  guide
}

guide_gengrob.guide_longticks <- function(guide, theme) {
  dir <- guide$direction
  guide <- NextMethod()
  is_ticks <- grep("^ticks$", guide$layout$name)
  ticks <- guide$grobs[is_ticks][[1]]
  if (dir == "vertical") {
    ticks$x1 <- rep(tail(ticks$x1, 1), length(ticks$x1))
  } else {
    ticks$y1 <- rep(tail(ticks$y1, 1), length(ticks$y1))
  }
  
  guide$grobs[[is_ticks]] <- ticks
  guide
}

ggplot(iris, aes(Sepal.Length, y = Sepal.Width, fill = Petal.Length))+
  geom_point(shape = 21) +
  scale_fill_continuous() +
  guides(fill = guide_longticks(ticks = TRUE, ticks.colour = "black"))

^{Created on 2020-06-24 by the reprex package (v0.3.0)}

EDIT:

Also try this alternative constructor if you want flat colours in between ticks:

guide_longticks <- function(...) {
  guide <- guide_colorsteps(...)
  class(guide) <- c("guide", "guide_longticks", "colorsteps", "colorbar")
  guide
}

EDIT2:

The following gengrob function would also delete the smaller ticks, if you want cleaner vector files. It kind of assumes that they are the last half of the ticks though:

guide_gengrob.guide_longticks <- function(guide, theme) {
  dir <- guide$direction
  guide <- NextMethod()
  is_ticks <- grep("^ticks$", guide$layout$name)
  ticks <- guide$grobs[is_ticks][[1]]
  n <- length(ticks$x0)
  if (dir == "vertical") {
    ticks$x0 <- head(ticks$x0, n/2)
    ticks$x1 <- rep(tail(ticks$x1, 1), n/2)
  } else {
    ticks$y0 <- head(ticks$y0, n/2)
    ticks$y1 <- rep(tail(ticks$y1, 1), n/2)
  }
  
  guide$grobs[[is_ticks]] <- ticks
  guide
}

How to make discrete gradient color bar with geom_contour_filled?

I believe this is different enough to my previous answer to justify a second one. I answered the latter in complete denial of the new scale functions that came with ggplot2 3.3.0, and now here we go, they make it much easier. I'd still keep the other solution because it might help for ... well very specific requirements.

We still need to use metR because the problem with the continuous/discrete contour persists, and metR::geom_contour_fill handles this well.

I am modifying the scale_fill_fermenter function which is the good function to use here because it works with a binned scale. I have slightly enhanced the underlying brewer_pal function, so that it gives more than the original brewer colors, if n > max(palette_colors).

update
You should use guide_colorsteps to change the colorbar. And see this related discussion regarding the longer breaks at start and end of the bar.

library(ggplot2)
library(metR)

mybreaks <- c(seq(-2,2,0.5), 3:5, seq(7,11,2))

ggplot(faithfuld, aes(eruptions, waiting)) +
  metR::geom_contour_fill(aes(z = 100*density)) +
  scale_fill_craftfermenter(
    breaks = mybreaks, 
    palette = "Spectral", 
    limits = c(-2,11),
    guide = guide_colorsteps(
      frame.colour = "black", 
      ticks.colour = "black", # you can also remove the ticks with NA
      barwidth=20)
  ) +
  theme(legend.position = "bottom")
#> Warning: 14 colours used, but Spectral has only 11 - New palette created based
#> on all colors of Spectral

## with uneven steps, better representing the scale 
ggplot(faithfuld, aes(eruptions, waiting)) +
  metR::geom_contour_fill(aes(z = 100*density)) +
  scale_fill_craftfermenter(
    breaks = mybreaks, 
    palette = "Spectral", 
    limits = c(-2,11),
    guide = guide_colorsteps(
      even.steps = FALSE,
      frame.colour = "black", 
      ticks.colour = "black", # you can also remove the ticks with NA
      barwidth=20, )
  ) +
  theme(legend.position = "bottom")
#> Warning: 14 colours used, but Spectral has only 11 - New palette created based
#> on all colors of Spectral

Function modifications

craftbrewer_pal <- function (type = "seq", palette = 1, direction = 1) 
{
  pal <- scales:::pal_name(palette, type)
  force(direction)
  function(n) {
    n_max_palette <- RColorBrewer:::maxcolors[names(RColorBrewer:::maxcolors) == palette]
    
    if (n < 3) {
      pal <- suppressWarnings(RColorBrewer::brewer.pal(n, pal))
    } else if (n > n_max_palette){
      rlang::warn(paste(n, "colours used, but", palette, "has only",
                    n_max_palette, "- New palette created based on all colors of", 
                    palette))
      n_palette <- RColorBrewer::brewer.pal(n_max_palette, palette)
      colfunc <- grDevices::colorRampPalette(n_palette)
      pal <- colfunc(n)
    }
    else {
      pal <- RColorBrewer::brewer.pal(n, pal)
    }
    pal <- pal[seq_len(n)]
    if (direction == -1) {
      pal <- rev(pal)
    }
    pal
  }
}

scale_fill_craftfermenter <- function(..., type = "seq", palette = 1, direction = -1, na.value = "grey50", guide = "coloursteps", aesthetics = "fill") {
  type <- match.arg(type, c("seq", "div", "qual"))
  if (type == "qual") {
    warn("Using a discrete colour palette in a binned scale.\n  Consider using type = \"seq\" or type = \"div\" instead")
  }
  binned_scale(aesthetics, "fermenter", ggplot2:::binned_pal(craftbrewer_pal(type, palette, direction)), na.value = na.value, guide = guide, ...)
}

ggplot: Is there a way to add a color coded bar annotation to the right of the y-axis?

The annotate function can do exactly as you indicate. The think to remember is that discrete scales have a continuous scale underneath and that the positions of discrete categories is match(x, sort(unique(x)), so that you bar should start around 3.5 for the iris dataset.

library(ggplot2)

ggplot(iris, aes(Species, y = Petal.Length)) +
  geom_violin() +
  annotate(
    xmin = 3.5, xmax = 3.75,
    ymin = c(-Inf, 3, 6),
    ymax = c(3, 6, Inf),
    geom = "rect",
    fill = c("dodgerblue", "tan", "red")
  )

^{Created on 2021-07-16 by the reprex package (v1.0.0)}

---

Related Topics